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Biomedical subjects

E Gregory

Publications and source records attributed to E Gregory.

At least 19 recordsLinked to original sources
PubMed2000

National school nurse certification. Part I: An ongoing process.

The National Association of School Nurses proposed the concept of certification for school nurses in the 1970s. The development and evolution of the school nurse certification process, from concept to reality, is described in this article. It is the first of a 2-part series on national certification for school nurses. Part 2 will examine issues and answer questions about the certification, give information from past and current presidents and certified school nurses about their experiences, and present a forecast about the future of school nurse certification.

Certification↗
PubMed1997

Fatal agricultural injuries in North Carolina by race and occupation, 1977-1991.

Medical examiner reports and death certificates were reviewed for all fatal agricultural injuries (n = 228) that occurred on-the-job in North Carolina between 1977 and 1991. Data were collected on the decedents' age, gender, race, data and time of injury, means of injury, and occupation. Annual workforce estimates were derived from the 1980 and 1990 US Census of the Population. Overall, 54% of the fatal injuries were due to tractors. Farmers who suffered fatal injuries tended to be older (median age = 56 years) and Caucasian (87%), while farm workers who died on the job were younger (median age = 35 years) and more often African-American (60%). The crude mortality rate for farmers was 38 per 100,000 worker-years; the crude rate for farm laborers was 16 per 100,000 worker-years. Age-adjusted fatal injury rates were 2.5 times higher among African-American farmers than among Caucasian farmers; furthermore, between 1977 and 1991 the rate of fatal injury among African-American farmers increased an estimated 14.7% per year. African-American farmers in North Carolina have experienced rising rates of fatal injuries at a time when employment in the industry is declining due to consolidation of farm ownership and foreclosures of African-American owned farms. In order to address the growing racial disparity in farm fatalities, efforts need to be made to improve the conditions under which African-American farmers are working.

Accidents, Occupational↗
PubMed1997

Cancer mortality among electric utility workers exposed to polychlorinated biphenyls.

OBJECTIVES: To assess whether excess mortality from cancer, malignant melanoma of the skin, and cancers of the brain and liver in particular, is associated with long term occupational exposure to polychlorinated biphenyls (PCBs). METHODS: An epidemiological study of mortality was conducted among 138,905 men employed for at least six months between 1950 and 1986 at five electrical power companies in the United States. Exposures were assessed by panels composed of workers, hygienists, and managers at each company, who considered tasks performed by workers in 28 job categories and estimated weekly exposures in hours for each job. Poisson regression was used to examine mortality in relation to exposure to electrical insulating fluids containing PCBs, controlling for demographic and occupational factors. RESULTS: Neither all cause nor total cancer mortality was related to cumulative exposure to PCB insulating fluids. Mortality from malignant melanoma increased with exposure; rate ratios (RRs) relative to unexposed men for melanoma were 1.23 (95% confidence interval (95% CI) 0.56 to 2.52), 1.71 (0.68 to 4.28) and 1.93 (0.52 to 7.14) for men with < 2000, > 2000-10,000, and > 10,000 hours of cumulative exposure to PCB insulating fluids, respectively, without consideration of latency. Lagging exposure by 20 years yielded RRs of 1.29 (0.76 to 2.18), 2.56 (1.09 to 5.97), and 4.81 (1.49 to 15.50) for the same exposure levels. Mortality from brain cancer was modestly increased among men with < 2000 hours (RR 1.61, 95% CI 0.86 to 3.01) and > 2000-10,000 hours exposure (RR 1.79, 95% CI 0.81 to 3.95), but there were no deaths from brain cancer among the most highly exposed men. A lag of five years yielded slightly increased RRs. Mortality from liver cancer was not associated with exposure to PCB insulating fluids. CONCLUSIONS: This study was larger and provided more detailed information on exposure than past investigations of workers exposed to PCBs. The results suggest that PCBs cause cancer, with malignant melanoma being of particular concern in this industry.

Follow-Up Studies↗
PubMed1996

Genetic studies in Alzheimer's disease with an NACP/alpha-synuclein polymorphism.

The non-Abeta component of Alzheimer's disease amyloid (NAC) is copurified with amyloid from the brain tissue of Alzheimer's disease victims and is immunohistochemically localized to amyloid fibrils. NAC is a hydrophobic peptide fragment from the NAC precursor protein (NACP/alpha-synuclein) that is localized to presynaptic terminals. We used a polymorphic dinucleotide repeat sequence in a genomic clone of NACP for genetic association and linkage studies. Screening of Alzheimer's disease families failed to establish linkage between NACP and Alzheimer's disease. Nevertheless, one of the NACP polymorphisms (NACP allele 2) was shown to have significant association with healthy elderly control individuals with apolipoprotein E risk. This may indicate a possible protective function of the allele.

Aged↗
PubMed1992

Pathway from the zona incerta to the superior colliculus in the rat.

In order to test the proposal that the zona incerta contributes to the generation of orienting movements, we examined the synaptic relationships between the incertotectal pathway and the cells of origin of the predorsal bundle. The predorsal bundle cells give rise to the major premotor pathway from the superior colliculus to the brainstem gaze centers. First, cytochrome oxidase histochemistry, gamma-aminobutyric acid (GABA), and glutamic acid decarboxylase (GAD) immunocytochemistry, and the axonal transport of markers were used to define the borders of a ventral subdivision of the zona incerta. This subdivision projects topographically to the same sublamina of the intermediate grey layer of the superior colliculus that contains the vast majority of the predorsal bundle cells. Experiments in which incertotectal cells were labeled by both retrograde transport and immunocytochemistry showed that this pathway is GABAergic. Retrograde and anterograde experiments also showed that this pathway is reciprocated by a pathway from the intermediate grey layer of the superior colliculus to the same ventral subdivision of the zona incerta. Finally, experiments combining axonal transport and electron microscopic methods showed that the incertotectal pathway is the source of a monosynaptic GABAergic input to the cells of origin of the predorsal bundle. The ventral subdivision of the zona incerta is contrasted with a second source of GABAergic input to the predorsal bundle cells, the substantia nigra pars reticulata.

Afferent Pathways↗
PubMed1988

Care and sterilization of endourologic instruments.

All endourologic instruments must be handled properly if they are to continue to function properly. Care must be taken in washing and sterilizing of this equipment, as not all endoscopic equipment can endure all methods, and people who are working with these instruments must be taught the proper care and sterilization methods of each. For example, fiberoptic telescopes and light cables must never be autoclaved; ethylene oxide is the method of choice. Disinfectant is an alternative. Loops, sheaths, high-frequency cables, resectoscopes, and working elements should be sterilized by ethylene oxide. Loops and high-frequency cables should not be soaked in a disinfectant, but other instruments may be soaked. All instruments should be dried before sterilization. Too much emphasis cannot be placed on the importance of proper storage of these very fragile fiberoptic instruments. With proper care and sterilization, these instruments will need fewer repairs and function properly for a longer time.

Disposable Equipment↗
PubMed1984

Postnatal maturation of cerebellar mossy and climbing fibers: transient expression of dual features on single axons.

We have studied the form and fine structure of developing afferent axons in postnatal mouse cerebellum, before and during the formation of synaptic connections. In slices of fresh brain, bundles of axons were injected with horseradish peroxidase (HRP), and individual axons were examined in the light and electron microscopes. At birth, before formation of cortical layers, axons with growing tips are rare in the peduncular tracts but instead ramify throughout the cerebellar anlage. All axons have similar structures; they branch infrequently and terminate in bud-like tips and/or small growth cones. Growth cones contain small and large vesicles in the flank and small vesicles in filopodia. Typical mossy and climbing fiber branching patterns and bouton shapes are recognizable after postnatal day (P) 5, even though fibers are still intermingled in a plexus beneath the newly formed Purkinje cell layer. Climbing fiber-like axon arbors are highly branched and covered with small foliate growing tips that contact Purkinje cells. Mossy fiber-like branches have large irregular expansions that give rise to long filopodia and resemble growth cones seen in vitro. The flanks of these growth cones contact granule cell dendrites and form glomeruli typical of mossy fibers, whereas the filopodia make primitive contacts or are associated with coated vesicles in adjacent profiles. A novel finding is the occurrence during the second postnatal week of many single axons that simultaneously have the morphology and synaptic connections of both climbing and mossy fibers. These "combination" axons have some branches that extend into the granule cell layer and others that enter the Purkinje cell layer, with the shape and synaptic connections of terminals on each branch type corresponding to the respective layer. Climbing fiber-like branches, including those on combination fibers, extend over several adjacent Purkinje cells. Combination fibers are rare in late postnatal or adult stages. These results suggest that long after arrival in the cerebellum, afferent axons have similar elementary forms and overlap in their projections. Mature axonal forms are not exhibited until cellular layers develop. During a limited period of postnatal maturation, some axons have dual morphologies and synaptic relations with appropriate and inappropriate partners. These aspects of cerebellar axonal development, particularly the transient exuberant branching onto two types of target cells, offer a valuable opportunity to examine, in developing cerebellum, the sorting out of afferents and the formation of specific synaptic connections.

Animals↗
PubMed1983

The effects of neonatal androgenization of female hamsters on adult preference for female hamster vaginal discharge.

The effects of neonatal exposure of hamsters to androgen on the development of an adult preference for female hamster vaginal discharge (FHVD) were investigated. Three groups treated on Days 2-3 postpartum (females administered testosterone propionate (TP) in a peanut oil base, females administered oil alone, and males administered oil alone) were combined factorially with four sequential adult conditions (intact, post-gonadectomy, post-gonadectomy plus TP therapy, and post-gonadectomy) to produce twelve experimental conditions. Statistical analysis indicated that neonatal oil females did not show a significant FHVD preference in any adult condition. Neonatal TP females displayed a significant FHVD preference only in the post-gonadectomy plus TP condition. Males retained a significant FHVD preference in all the adult conditions, although the preference shown in the two adult hormonal conditions (intact and post-gonadectomy plus TP) was significantly higher than the preference shown in the two nonhormonal conditions.

Animals↗